We report a patient with a refractory testicular non-seminomatous germ cell tumor (NSGCT) who developed therapy-related leukemia (TRL) after undergoing salvage chemotherapy and multiple operations for repeat recurrences. Fifty months after the initial therapy, pancytopenia and myeloblasts were observed in the patient's peripheral blood while the patient was undergoing salvage chemotherapy for a fifth recurrence. A bone marrow examination showed evidence of myelodysplastic syndrome (MDS) and refractory anemia with excess of blasts in transformation (RAEB in T) under French-America-British (FAB) classification. Cytogenetic 5q-/7q- abnormalities were also observed. The patient had received a total dose of 189g/m2 of Ifosfamide, 8,250mg/m2 of Etoposide and 1,450 mg/m2 of Cisplatin; therefore, he was diagnosed as having TRL/MDS. The patient has received induction chemotherapy for TRL with Cytarabine, Daunorubicin and Fludarabine while a bone marrow transplantation has been scheduled. Recently, TRL associated with chemotherapy are being reported with increasing frequency in the literature. Since early detection and treatment are necessary for the management of TRL, peripheral blood examinations should be performed after a diagnosis of refractory germ cell tumor has been made. If pancytopenia is detected, bone marrow and cytogenetic examinations should be immediately performed to rule out TRL.